1. Field of the Invention
The present invention is related to firearm caliber conversions. More specifically, the present invention relates to a barrel extension that mates a barrel to a rifle to safely achieve more accurate firing of smaller caliber ammunition than the firearm's initial configuration.
2. Description of Related Art
In order to fire a different caliber in a firearm than what the firearm was initially designed to accommodate, a caliber conversion kit or device needs to be installed in the desired firearm. Caliber conversion kits and devices which change the caliber of ammunition a firearm fires have been known in the art. The primary purpose of many of these conversion kits is to enable the firing of less expensive ammunition. Typically lower caliber ammunition is less expensive than higher caliber ammunition, although cartridge size and other factors can affect the price of the ammunition.
For example, the CMMG™.22LR conversion Model Alpha (as shown in FIG. 8) available from CMMG Inc. P.O. Box 369 Fayette, Mo. 65248 is a .22LR caliber rim-fire blowback device which replaces the standard bolt/bolt carrier assembly in the AR15 family of firearms. It should be noted that the standard bolt/bolt carrier assembly in the AR15 family are gas operated systems. The CMMG™ .22LR conversion allows for the use of .22LR ammunition in place of 5.56 NATO or .223 Rem ammunition. This particular conversion is a blow-back operated sub-caliber conversion that allows for the firing of .22LR ammunition in an AR15 or M16 firearm. The CMMG™ .22 LR conversion also includes a magazine adapted for holding .22LR ammunition and having the same or similar exterior dimensions as a standard AR15 magazine adapted to hold 5.56 NATO or .223 Rem ammunition.
One shortcoming of this type of conversion is that it still utilizes a standard AR15 barrel extension and barrel with standard diameter bore and rifling twist rate resulting in an improper fit of the .22LR bullet to the barrel. This arrangement results in bullet wobble and inaccuracy of the firearm.
There is a need for a device and/or kit to safely improve the accuracy of a rifle that is firing sub-caliber ammunition.